Field of the Invention
The present disclosure relates to a transparent electrode and a method of manufacturing the same, and more particularly to a transparent electrode including conductive nanowires and porous nanoparticles and having low sheet resistance, enhanced adhesion to a substrate, enhanced dispersion, and low surface roughness, and a method of manufacturing the same.
Description of the Related Art
Research into electronic devices having flexibility and elasticity is actively underway as portability of electronic equipment is emphasized. A variety of flexible electronic devices have been developed as a result of such research. A flexible display is a representative example of such flexible electronic devices.
A flexible display can be freely bent or folded due to flexibility thereof, thus being applicable to a variety of portable electronic equipment such as mobile phones. In such a flexible display, a flexible and transparent electrode is used. Indium-tin oxide (ITO) is mainly utilized as a conductive oxide of such a transparent electrode.
An indium-tin oxide (ITO) thin film used in transparent electrodes has superior conductivity and transparency, but is brittle. Accordingly, when the indium-tin oxide (ITO) thin film is bent or folded, there are problems such as crack occurrence and thus mechanical stability is decreased, which may cause sheet resistance increase.
In addition, upon use of such an indium-tin oxide (ITO) thin film, manufacturing costs are high due to scarcity of indium as a material of the indium-tin oxide (ITO) thin film.
So as to address the aforementioned problems of an indium-tin oxide (ITO) thin film, a related patent document described below suggests a transparent electrode to which carbon nanotubes (CNTs) as a thin film are applied.
However, existing transparent electrodes including carbon nanotubes are very sensitive to moisture, thus easily adsorbing moisture. Accordingly, sheet resistance is greatly increased and thus over-coating is required.
In addition, carbon nanotubes have superior flexibility, compared to indium-tin oxide (ITO), but have poor electrical and optical characteristics.
Accordingly, as a solution to address existing problems occurring in a transparent electrode, a technique of large-area coating of a variety of nanowires, such as silver nanowire networks (AgNWs) or nanowire meshes on a flexible polymer substrate using various solution coating techniques and a method of utilizing such a technique were suggested.
However, nanowire meshes have problems such as chemical bonding with a material on the electrode, limitation of uniform interfacial contact due to rough surfaces thereof (Rrms), and electrical short occurrence in device construction due to partial non-contact with a longitudinal section.
In addition, nanowire-based electrodes have highly variable sheet resistance (Rs) due to non-uniform characteristics of nanowire meshes.